BELFAST, Maine — Dressed in their worn Maine Maritime Academy work uniforms, the two new owners of Goose River Hydro looked capable, confident — and every day of their 21 years.

Nicholas Berner, a junior midshipman of Swiss descent who lives in Corinth, Vt., and Nicholas Cabral, of Kennebunk, have been friends since their first year at the Castine college. They both study marine systems engineering. And they were both in a renewable energies class last spring when the professor gave a presentation about hydropower and mentioned the series of three power plants and five dams on the Goose River in Belfast that was for sale.

“I looked at Nick jokingly, kind of, and said, ‘Let’s buy these dam things,’” Cabral said this week from the old mill office.

But the joke took root after the two young men called Cathy Gleeson, who ran the hydropower utility with her late husband, Larry Gleeson, for more than 30 years and was eagerly looking for a buyer. She had talked for a while with the city of Belfast, whose officials were intrigued by the chance to generate as much as 1.5 million kilowatt hours of electricity per year. But city councilors last spring let the option to purchase Goose River Hydro from Gleeson for $125,000 expire after estimates for capital improvements and annual operating costs added up to as much as $4.6 million over 20 years.

Berner and Cabral kept mulling over the chance to own and run their own hydro power plant. They worked on a business plan and considered the pros and the cons — which included the fact that they know two hardworking guys who would work for cheap.

“We’re in college. We’re willing to do this work for ourselves,” Berner said.

At school, they’ve learned how to weld and machine. They’ve done a lot of problem solving when it comes to working with diesel engines and steam turbines. They said that their course instructors have been willing to share their knowledge and help them find contacts in the hydropower world. And they would look at the hydro power plant as a project that should allow them to figure out how to use it as a testing facility for turbine development.

“We have to do a big project capstone at the end of our five years,” Cabral said. “This is definitely going to be ours.”

The series of dams are located on a 10-mile stretch of the Goose River between the southern outlet of Swan Lake and Belfast Bay. More than a century ago, there were 33 dams on the river, all of which used the tumbling water to generate power to make axe handles, grind grain, mill lumber and make leather board for Maine’s shoe industry. Goose River Hydro has the only remaining, functional dams.

Thanks to a private family loan, the two were able to buy the company from Gleeson for a sum that they prefer to keep private. They closed on Valentine’s Day.

“It was kind of surreal,” Cabral said. “It didn’t hit me until we had to pay our first electric bill. Once we start generating power, I think our electric bills will be a good thing. They’ll be green instead of red.”

Gleeson has been very helpful, they said, readily sharing her experience and knowledge of running the dams and power plants.

“We’ve been going through a pretty steep learning curve,” Cabral said a few weeks ago after a Belfast City Council meeting where he introduced himself to the community.

“They’re really jumping in feet-first,” Gleeson said of the two young men.

Cabral and Berner said that while their long-term plans are still somewhat under construction, they want to try to develop a hydropower system that could be adapted for use in other parts of Maine and New England.

“We want to use our facility and testing site for prototypes,” Cabral said.

Thomas Kittredge, the economic development director for Belfast, said this week that the city is glad to work with Berner and Cabral to assist them in applying for grants and may explore the possibility of purchasing power from them in the future.

“It’s great that the private sector is choosing to rehabilitate this facility,” he said. “It’s nice that there will be new investments, and these dams put back in productive use. We want to encourage them and support them any way we can.”

Cabral and Berner said that what they lack in age and experience, they bring in enthusiasm and energy.

“We may be young, but our heart’s in it,” Cabral said. “We want to do well.”